The water might be clean enough to drink if the other constituents of the water are benign. I am guessing your question could be related to how aquatic plants can remove bad material such as animal waste products which is faeces & urine. read more
Aquatic plants play an important role in maintaining a healthy water garden or pond. They not only absorb carbon dioxide and release oxygen into the water, improving the environment for fish, but absorb nutrients from the water as well. read more